Simulated Experiments on IOL Power Calculation Using Anterior Segment OCT

1
Simulated Experiments on IOL Power Calculation
Using Anterior Segment OCT

• Dong Hyun Jo, M.D.,1,2 Mee Kum Kim, M.D.,1,2 Won
  Ryang Wee, M.D.1,2

Financial disclosure All authors have no
proprietary interest in methods described in this
article.
1Department of Ophthalmology, Seoul National
University College of Medicine, Seoul, Korea,
2Seoul Artificial Eye Center, Seoul National
University Hospital Clinical Research Institute,
Seoul, Korea
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Purpose

• To compare the method of calculating intraocular
  lens (IOL) power by anterior segment optical
  coherence tomography (AS-OCT) with the clinical
  history (Single-K) and Double-K methods

3
Methods

• Patients
• who had undergone LASEK from July 1, 2009 to June
  30, 2010
• Preoperative and postoperative examinations
• Best spectacle-corrected visual acuity
• Intraocular pressure
• Anterior and posterior segment examinations
• Slitlamp biomicroscopy
• Funduscopy
• Automated keratometry
• Anterior segement optical coherence tomography
  (AS-OCT)
• LASEK was performed using Visx Star S4 (VISX
  Inc., Santa Clara, CA).

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Methods

• Methods of IOL power calculation SRK/T formula
• Double-K method devised by Aramberri
• Preoperative keratometric value ? anterior
  chamber depth (ACD)
• Postoperative keratometric value ? the power of
  IOL
• Single-K method Clinical history method
• AS-OCT method
• we utilized corneal height (Ch) as measured by
  AS-OCT in the IOL power calculation

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Methods AS-OCT method
Ch
2, 3
1
1. A horizontal line was drawn to connect both
ends of the anterior chamber angles 2. A vertical
line was drawn from the posterior surface of the
corneal vertex to fall on the horizontal line.
3. The length of the vertical line was
designated as Ch.
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Methods

• Comparison of Ch according to myopic status
  before and after the refractive surgery
• Low myopia (gt-3 D)
• Moderate myopia (-3 D, gt-6 D)
• High myopia (-6 D)
• Comparison of the results among 3 methods with
  each other

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Results

• Demographic, Refractive, and Keratometric Data
  73 eyes of 37 patients

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Results

• Comparison Between Preoperative and Posoperative
  Ch According to the Preoperative Myopic Status
• Chpre preoperative corneal height
• Chpost postoperative corneal height
• ? Ch difference between preoperative and
  postoperative cornealheight
• P lt 0.05

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Results

• Corneal Height Estimated Using the Different
  Methods

The differences between values obtained with
AS-OCT method and those obtained with the other 2
methods were statistically significant (P lt 0.001
in both analyses).
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Results

• Intraocular Lens Power Calculated Using the
  Different Methods

Pemme IOL power to get emmetropia Pemme
obtained using AS-OCT method was higher than
that obtained using the Single-K method lower
than that obtained using the Double-K method .

(P lt 0.001
in both analyses)
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Conclusions

• We demonstrated that Ch as measured by AS-OCT
  could be utilized in IOL power calculation after
  corneal refractive surgery.